#include <iostream>
using namespace std;
#include <bits/stdc++.h>

int main() {
	// your code goes here
	
	int arr[]={1,2,3,4,5,6};
	int n;
	cin>>n;
	int k;
	cin>>k;
	sort(arr,arr+n);
	int i=0,j=n-1,sum=0,count=0;
	for(i=0,j=n-1;i<n && j>=0;i++)
	 {
	 	sum=arr[i]+arr[j];
	 	while(sum>k && i!=j)
	 	 {
	 	 	j--;
	 	 	sum=arr[i]+arr[j];
	 	 }
	 	 if(i==j)
	 	  {
	 	  	break;
	 	  }
	 	  
	 	  count+=(j-i);
	 }
	 cout<<count;
	
	return 0;
}